By maria171 - 08-01-2019 08:43
As stated in the manual regarding deterioration:
“Training during deterioration:
During the deterioration period, you will be able to gain skill balls in attributes other than Speed and Stamina. You will then see two entries in the daily Training Report, one for the deterioration and one for any improvement in the other skill trained. It will not help the Player if you try to train him in Speed or Stamina at this time.”
So to answer your question, deterioration cannot be stopped even if you try to train them with coach.